Due to development of thin film growth techniques and device materials, light emitting devices such as light emitting diodes and laser diodes using III-V or II-VI compound semiconductor materials may realize red, green, blue and various color light and ultraviolet light and may realize white light having high efficiency through fluorescent materials or color mixing.
Due to development of such techniques, those light emitting devices have been increasingly applied not only to display devices but also to transmission modules of light communication means, light emitting diode backlights substituting for cold cathode fluorescent lamps composing backlights of liquid crystal displays (LCD), white light emitting diode lighting apparatus substituting for fluorescent lamps or incandescent lamps, head lights of vehicles and street lights.